ABSTRACT
All sound as we know it is a matter of vibration of the atmosphere, reaching the ear with a rapidity that varies roughly from forty to forty thousand impulses per second. Something initiates a disturbance in the air, and the impulse is distributed by waves which go out in circular fashion, as we see when we throw a stone into the still waters of a pond. The water does not actually travel to the margin of the pond, and neither does the atmosphere itself move from place to place; but the wave passes through the air, as an impulse may pass through a row of stationary billiard balls in contact and send only the last one flying.
